Cook rigatoni according to package directions.,Reserve pasta water and set pasta aside.,Heat olive oil in a large skillet to medium-high heat.,Add sliced fennel and cook 12 minutes, until starting to soften.,Add sausage and saute 12 minutes until it starts to brown, then add garlic and saute 3060 seconds, until fragrant.,Add artichokes and season with a dash of salt, pepper, crushed red pepper flakes and oregano; stir to combine.,______,Cook 12 minutes, until sauce starts to thicken.,Stir in half-and-half and add cooked pasta to the pot.,Season with another dash of salt and pepper and toss sauce with pasta.,Fold in Parmesan cheese and arugula and distribute pasta into bowls.,Serve.